Partial denture constructions



Jan. 11, 1966 A. RITTER 3,

PARTIAL DENTURE CONSTRUGTIONS Filed May 13, 1963 INVENTOR.

ARTHUR R ITTER ATTORNEYS United States Patent Office 3,22%,lh PatentedJan. 11, 1966 3,228,106 PARTIAL DENTURE CONSTRUCTIONS Arthur Ritter,2039 Rittenhouse Square, Philadelphia 3, Pa. Filed May 13, 1963, Ser.No. 279,738 14 Claims. (Cl. 325) This invention relates to removablepartial denture constructions. More particularly it relates to dentureswherein resilient axial retainers are used to keep the denture in placeand co-act with both novel guidance means and means for positioning thedenture with respect to the gingiva. It also relates to crownedabutments particularly suited for use in connection with theconstructions of the invention.

An object of this invention is to provide simple and effective denturesupporting means which are adapted to hold a denture firmly in place,despite wear, and to permit its ready and accurate alignment.

It is also an object of the invention to provide dentures constructed ina manner which permits easy removal for oral hygiene.

It is a further object of the invention to provide dentures whereinadjustment to compensate for wear is simplified and the useful life ofthe denture thus extended.

Still another object of the invention is to provide a dentureconstruction, the alignment of which is not effected by direct wear,indirect wear or at resorption.

A general object of the invention is to simplify and improve theconstruction of means for holding removable dentures in place.

A further object of the invention is to provide a dental construction inwhich a minimum amount of wear occurs due to movement of the denture inmastication such as is caused by the yielding of the gum tissue on whichthe denture is supported.

Still another object of the invention is to provide a dentureconstruction wherein the connectors of the partial denture terminate ina clasp which is attached to an abutment in a manner as to be invisiblefrom the anterior of the mouth but which, nonetheless, provides superiorretention and alignment characteristics.

It is also an object of this invention to provide crowned abutmentsconstructed in a novel manner which permit permanent spacing of thedenture with respect to the gingiva and simultaneously provide forguidance and re tention thereof.

Another object of this invention is the provision of a dental prosthesiswhich can be anchored to permanent crowned abutments without marring theappearance of the user with visible clamps and other readily apparentstructure.

Other objects of this invention are to provide improved dentures of thecharacter described which are sturdy in construction, economical andquick to produce, and highly efficient in operation.

These and other objects of the invention will be apparent to thoseskilled in the dental art from the following description, when read inconjunction with the accompanying drawings, in which:

FIGURE 1 represents a fragmentary view of the human maxilla projectedupon the occlusal plane illustrating a removable partial dentureconstruction of the invention as it would appear in place, ready foruse.

FIGURE 2 is a fragmentary sectional view taken along line 22 of FIGURE1.

FIGURE 3 is a fragmentary sectional view taken along line 33 of FIGURE1.

FIGURE 4 represents a detail of a resilient axial retainer of theinvention.

FIGURE 5 represents a perspective view of a typical crowned abutmentsuitable for use in the invention.

FIGURE 6 represents a partial fragmentary sectional view showing amodified combined guidance-retention means of the invention.

Referring now to the figures, wherein like numerals designate likeparts, and with particular attention to FIG- URE 1 it will be observedthat a removable partial denture 16 is mounted in the human mandible 11in order to provide the wearer with a complete set of teeth. Those teethnot provided by the removable denture 10 may include, for instance, theleft central incisor 12, the right central incisor 13, the left lateralincisor 14, the right lateral incisor 15, the left canine 16, the rightcanine 17, the left first pre-molar 18, the right first pre-molar 19,and the left second pre-molar 2t}. Teeth 12 to 17 inclusive may be thewearers own natural teeth, or, depending on the case, may be crownedteeth which may, if desired, be tied together for strength. However,left first premolar 13, left second pre-molar 20 and right firstpre-molar 19 are crowned teeth which, although fixed in the mouth andnon-removable, are not the wearers natural teeth but have beenconstructed by the technician and mounted by the dentist. Because oftheir function in retention of the partial denture 19, these teeth arereferred to as abutments. As will be fully described, abutments of theinvention have special constructions which enable them to co-act withthe partial denture 10. The abutments may be tied to each other and/ orto permanent natural teeth in a conventional manner such as by tyingmeans 21.

The abutments of the invention may be best understood by a considerationof FIGURE 5 wherein a typical abutment, such as, for instance, rightfirst pre-molar I9 is shown.

Abutment 19 which may be considered representative, comprises a bitingsurface 22, in the occlusal plane, and an enamel-simulating anteriorfacade 23, which provides the natural appearance so desirable as anobject of any dental reconstruction. As previously stated, abutmentssuch as 19 are crowned teeth and are fixedly attached by any of theconventional methods of the prior art. However, the abutments of theinvention are provided with a plurality of parallel axial lingualchannels which are spaced about the lingual perimeter of the tooth. As

shown in the particular embodiment being described, twoguidancechannels, 24 and 25, are provided as Well as one axial retention channel26. These channels are invisible when viewed from the exterior of themouth. It is preferred to space channel 24 and channel 26 perimetricallyabout apart. The abutment is further provided with an arcuate lingualshoulder 27 shown, in this case, connecting channels 24 and 25. It isthe cooperation between the guidance channels and the lingual shoulderwhich imparts occlusal rigidity and freedom from rotation to the dentalstructure and it is the shoulder which serves to keep the partialdenture in spaced relationship to the gingiva 28. Consequently, rigidityis enhanced when the guidance grooves are perimetrically spaced about180 apart and the shoulder connecting them is thus elongated to providea longer arcuate bearing surface.

Returning now to a consideration of FIGURE 1 it will be noted thatabutment 19 which has just been described in detail is but one of threeabutments (eg 18, 19 and 20). Abutment 18 is provided with a guidancechannel 29 and a retention channel 30. Similarly, abutment 24 isprovided with a guidance channel 31 and a retention channel 32. All ofthe abutments are provided with a shoulder such as 27. In brief, eachabutment must comprise at least one guidance channel and at least oneaxial retention channel as well as an arcuate lingual shoulder.

The teeth shown in FIGURE 1 which are neither natural teeth nor crownsare supplied by the partial denture 10. These partial denture mountedteeth include, for instance, left first molar 33, right second premolar34, right first molar 35, left second molar 36, right second molar 37,left third molar 38 and right third molar 39. These restored posteriorteeth may be mounted, as is well known in the art, on a plastic saddlewhich is an integral part of the partial denture 10. However, theinstant invention is concerned not with the manner in which the restoredteeth are made and attached to the partial denture but rather isconcerned with the manner in which the partial denture is held to andco-acts with the abutments.

The denture is provided with a plurality of connectors 40. A connectormay be defined as a part serving to connect the body of a partialdenture with those devices which grasp the abutments and hold thedenture in place. The devices of the terminal end of the connectors maybe broadly characterized as clasps.

The clasp which co-acts with abutment 19 is shown in FIGURES 1, 2 and 3.This clasp includes an arcuate rest portion 41, the underside of whichis adapted to abut the lingual shoulder 27 and resist displacement ofthe denture toward the gingiva 28. The exposed surface of the clasp 42conforms to the configuration of the abutment. One end of the rest isprovided with an integral axial strut 43 which is complementary incross-section to and adapted to be slideably received by channel orgroove 24. The rest is also provided, at the other end of portion 41,with a second axial strut 44 which is complementary to channel 25. Therest terminates in an integral sleeve portion 45 (see FIG- URE 4),proximate rentention channel 26, which is concavely contoured oppositechannel 26, as at 46. The sleeve is preferably formed with anenlargement 47 near its bottom which, functionally, serves as a fulcrum.

Lateral retention forces against the abutment 19 are provided by aresilient axial retainer, generally 48, which includes a lateral portion49 permanently affixed to the denture 10 and a vertical portion 50.Retainer 48 is preferably ovular in cross-section and complements bothchannel 26 and portion 46 of sleeve 45. Portion 50 is unattached todenture 10 and is free to move laterally with respect to rest portion45. In FIGURE 2 portion 50 is shown in phantom, as it would be when thedenture 10 is out of the mouth. However, when the denture is in place,as shown in FIGURE 2, portion 50 is bent back over fulcrum 47 and exertsa direct lateral retention force against abutment 19 and, as indicatedby the arrow, a downward reactive force on denture 10. Any wear whichoccurs between the denture and the abutment can be compensated for bybending of portion 50 to eliminate play.

The clasp used in connection with abutment 18 is generally similar andincludes resilient axial retainer 51 and an axial strut 52. The lateralforce against abutment 18 is, in this case, along a lingual-labial axisand provides indirect retention. The desideratum of 180 between channelsapplies to those clasps which counter-act rotational tendencies of thedenture and provide direct retention but does not necessarily apply, asin this case, where indirect retention is sought.

The clasp used in connection with abutment is also similar to the claspon abutment 19 and includes an axial strut 53 and a resilient axialretainer 54 connected by a rest portion 55. Here, however, retainer 54doubles as a guide strut as well as a source of lateralposterioranterior retention force against abutment 20. Clasps of theinvention are thus seen to require at least one axial retainer and atleast one axial strut since, where but two channels are provided in thecrowned abutment, the retention member also provides a guidance means.

FIGURE 6 shows another embodiment of the invention which is but amodification of the retention means of the previous embodiments. In thisembodiment a 4 crowned abutment 56 is provided with a guidanceretentionchannel 57. Denture 58, on which is mounted false tooth 59 is providedwith a connector terminating in a clasp comprising a partial axial strut60 which complements channel 57 in cross-section. However, unlike thestruts previously discussed, this partial strut extends only a shortdistance down from the occlusal plane. The balance of channel 57 isoccupied by an aligned resilient axial retainer 61 which is horizontallyfixed to denture it) but which, within channel 57, is free to exert alateral retention force against abutment 56.

Changes in the specific forms of the invention described above may bemade within the scope of what is claimed Without departing from thespirit of the invention.

Having described the invention, I claim:

1. In a partial denture construction a crowned abutment having anarcuate lingual shoulder and a plurality of parallel axial lingualchannels including at least one axial retention channel and at least oneguidance channel; and a connector terminating in a clasp removablymounted on said abutment which includes an arcuate rest portion abuttingsaid lingual shoulder thus resisting displacement of the denture towardthe gingiva, at least one axial strut complementary in cross-section andlength to said axial guidance channel and received thereby, and at leastone resilient axial retainer fitting within said axial retention channeland exerting a lateral force against said abutment.

2. The denture of claim 1 wherein said resilient retainer is ovular incross-section.

3. The denture of claim 1 wherein a partial strut is provided on saidclasp, to complement and fill any axially extending porton of saidretention channel not occupied by said resilient retainer.

4. The denture of claim 3 wherein said resilient retainer is ovular incross-section.

5. In a partial denture construction a crowned abutment including anarcuate lingual shoulder parallel to the occlusal plane and a pluralityof parallel axial channels spaced about the lingual perimeter of saidabutment including at least one axial retention channel and oneguidanceretention channel; and a connector terminating in a claspremovably mounted on said abutment which includes an arcuate restportion abutting said shoulder thus resisting displacement of thedenture toward the gingiva; at least one axial strut complementary incrosssection and length to said axial guidance channel and slideablymounted therein, a partial strut complementing said guidance-retentionchannel in cross-section, occupying the portion of said channel distalthe gingiva and slideably mounted therein, and a resilient axialretainer in alignment with said partial strut, occupying that portion ofthe length of said guidance-retention channel not occupied by saidpartial strut and exerting a lateral force against said abutment.

6. The denture of claim 5 wherein said resilient axial retainer isovular in cross-section.

7. In a partial denture construction a crowned abutment including anarcuate lingual shoulder and a plurality of parallel axial lingualchannels including at least one axial retention channel and at least oneguidance channel perimetrically spaced about apart; and a connectorterminating in a clasp removably mounted on said abutment which includesan arcuate rest portion abutting said lingual shoulder and thusresisting displacement of the denture toward the gingiva, at least oneaxial strut complementary in cross-section and length to said axialguidance groove and received thereby, and at least one resilient axialretainer fitting within said axial retention channel and exerting alateral force against said abutment.

8. The denture of claim 7 wherein said resilient retainer is ovular incross-section.

9. The denture of claim 7 wherein a partial strut is provided on saidclasp, to complement and fill that axially extending portion of saidretention channel not occupied by said resilient retainer.

10. The denture of claim 9 wherein said resilient retainer is ovular incross-section.

11. A crown for use as an abutment in partial denture constructioncomprising a hitting surface in the occlusal plane, an enamel simulatinganterior facade, a plurality of parallel axial lingual channelsperimetrically spaced apart including at least one axial retentionchannel and at least one guidance channel and an arcuate lingualshoulder between two of said channels.

12. The crown of claim 11 wherein two of said axial channels areperimetrically spaced about 180 apart.

13. A partial denture construction including a lingual clasp having anarcuate rest and a cross-section, in a plane parallel to the occlusalplane, conforming to an abutment on which the clasp is slideablyreceived, in a direction normal to the occlusal plane, said rest havinga flat underside to juxtapose a lingual abutment shoulder, at least oneintegral axial strut at one extreme of said clasp and at least oneresilient axial retainer at the other extreme of said clasp, saidresilient retainer terminating in a portion which is free to movelaterally with respect to said arcuate rest, and exert a lateral forceagainst an abutment.

14. The partial denture construction of claim 13 wherein said resilientretainer is ovular in cross-section.

References Cited by the Examiner UNITED STATES PATENTS 1,299,067 4/1919Underwood 325 1,591,155 7/1926 Craigo 32-5 2,631,373 3/1953 Timm 325RICHARD A. GAUDET, Primary Examiner.

ROBERT E. MORGAN, Examiner.

1. IN A PARTIAL DENTURE CONSTRUCTION A CROWNED ABUTMENT HAVING ANARCUATE LINGUAL SHOULDER AND A PLURALITY OF PARALLEL AXIAL LINGUALCHANNELS INCLUDING AT LEAST ONE AXIAL RETENTION CHANNEL AND AT LEAST ONEGUIDANCE CHANNEL; AND A CONNECTOR TERMINATING IN A CLASP REMOVABLYMOUNTED ON SAID ABUTMENT WHICH INCLUDES AN ARCUATE REST PORTION ABUTTINGSAID LINGUAL SHOULDER THUS RESISTING DISPLACEMENT OF THE DENTURE TOWARDTHE GINGIVA, AT LEAST